DE2146197A1 - Multi-dimensional stereophonic playback system - Google Patents

Description

. Whelm

■ 3 6831

VICrOR COMPAHY OP JAPAH, LiDD. Yokohama City, Japan

Multi-dimensional stereophonic playback system

The invention relates to a multidimensional stereophonic Playback system, and it deals in particular with an artificial, multi-dimensional 3-tereophonic playback system, for example an artificial four-channel system .

So far, multi-dimensional stereophonic playback systems have been used used, in which information signals originating from different sound sources that pass through a Space are distributed as multi-channel signals are recorded or transmitted and when the multi-channel signals can be reproduced by multiple playback sound sources on the playback side, whereby the Impression of stereophony is created. As a two-dimensional stereophonic playback system, it became a two-channel Stereophonic playback system used in which two channel signals i.e. left channel signals and right channel signals from Speakers are reproduced, which are arranged in front of the left and right in front of the listener. Lifting this two-channel System, four-channel stereophonic reproduction systems have also been proposed and used, for example

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stereophonic playback systems with four front channels in which playback sound sources for four channels are arranged in front of the listener (hereinafter referred to as "4-0" system) .furthermore, a stereophonic playback system, with two front channels and two rear channels, with two Channels for playback sound sources are arranged accordingly in front of and behind the listener (hereinafter referred to as a "2-2" system referred to) also a stereophonic playback system with three front channels and a back channel, in the arranged three channels of the playback sound sources in front of the listener and one channel of the playback sound source behind the listener (hereinafter referred to as the "3-1" plant).

It has been found that these four-channel stereophonic Playback systems the known two-channel stereophonic playback systems with regard to the Realism, the clarity of the tone and the direction of the sound, etc. are far superior. It should be noted, however, that a multi-dimensional stereophonic playback system with multiple channels, e.g. four channels, multi-channel program sources, for example requires four channels.

According to the invention, a multidimensional stereophonic reproduction system is to be provided, in which a stereophonic Playback sound image as with a "2-2" system or a "3-1" system artificially produced thereby can that two-channel program sources are used, as used in known stereophonic playback systems will.

In the above-mentioned "2-2 ^I1" systems and "3-1" systems, the sound emitted by the playback sound sources is mainly reflected sound behind the listener, room reverberation, etc. It is therefore conceivable to be a signal

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which is the return channel signal in the "2-2" system or reproduces the "3-1" system by a delay I reverberator to produce and this as a sound effect for an artificial multidimensional stereophonic Playback to use. However, a delay reverberator that is not as large as one is which is used for commercial purposes, but a simple one that is included in a device for domestic use can be used, generally unsatisfactory in their mode of operation, and they also only have one short lifespan. Besides, such a simple delay reverberation device is quite expensive, so that the

Manufacturing costs of the reproducing system become high. Consequently, a system employing the above-mentioned delay reverberation device cannot be used in practice because it has the disadvantages described.

According to the invention, a system is provided in which a direct sound component (for example a direct Sound component of a musical instrument or the human voice) from a signal source that is a two-channel Emits stereo signal, effectively extinguished or reduced and in which an indirect sound component that the reflected sound of a musical instrument or human voice, reverberation in a room and a Delay reverberation component artificially added during a mixing operation in recording is effectively generated and is also used. Direct sound from a sound source usually reaches the left and right microphones with the same sound pressure and the same · phase. However, the sound, the sound source, has the two microphones Reached little or no regular reflection after irregular reflection from the walls, floor, ceiling, etc. Properties that direct sound has, since it has a

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has an irregular sound path. This reflected irregularly Sound helps "to evoke a lively feeling for reality. When arranged according to of the present invention, a difference signal between the left channel signal and the right channel signal, the both together form the two-channel stereo signal, reproduced by the rear loudspeakers in order to thereby to emit indirect sound.

If the direct sound component of the two channel signals L and R contains different components that are in the Amplitude or phase are different from each other, then the direct sound component is in the effect sound signal inserted for artificial multi-dimensional stereophonic reproduction. The problem that arises, which will be described later, by appropriately setting the amplitude and phase of the direct sound component each channel signal L and R before the difference signal is obtained from the channel signals L and R, to be overcome.

When a low-frequency component is missing from the direct sound component play back anything from the rear speakers give ^v, then the realism and the indirect sound reduced constitutes a reproduction sound picture that gives a loose scattered impression, whereby a certain inconsistency, the feeling of disharmony or a psychological instability for the listener. The plant according to the invention is therefore designed to overcome this problem. According to the invention, a modified signal obtained by inverting (changing) the phase of a low frequency component of each channel signal is used to obtain a difference signal so that a low frequency component is not absent in the indirect sound components of the difference signals.

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It is therefore a general object of the invention to provide a new and improved system in which multiple channel signals be used for a stereophonic ^ reproduction, which are then artificially made more multidimensional, than it corresponds to the real number of channels. .

This object is achieved in that in a multi-dimensional stereophonic playback system, a first circuit for playback and emission of signals from several channels, which have a direct sound component and an indirect sound component, is provided from loudspeakers, which are each assigned to one of the channels Loudspeakers are arranged in front of a listener, that a second circuit is provided which processes the signals of the various channels in a matrix, whereby differential aials of each channel signal are obtained, and that these difference signals are reproduced or emitted by speakers that are next to or behind the Handset arranged siqd, the direct sound component being canceled out in these difference signals and they essentially only have the indirect sound components.

According to the invention, a system is to be created in which indirect sound, for example reflected sound or reverberation, is formed from difference signals from several channel signals and in which a multi-dimensional stereophonic reproduction circuit diagram is formed by reproducing and emitting indirect sound to the side or behind a listener .

According to the invention, a reproduction system is also to be created in which a direct sound component is almost completely extinguished and in which an extremely good difference signal component is provided.

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In the system according to the invention, the direct sound component almost completely extinguished, in that an amplitude correction circuit and a phase correction circuit be used.

According to the invention, a playback system is also to be provided in which the difference signals are caused by crosstalk from several channel signals by a suitable Crosstalk or crosstalk factor can be obtained in the opposite phase. If you get differential signals that one have low-frequency frequency components, then a multi-dimensional stereophonic reproduction sound field results, where you have a vivid feeling for reality and where you don't have a certain dissatisfaction without that A feeling of disharmony arises for the listener.

Embodiments of the invention are described below by way of example with reference to the drawings. Show:

Pig. 1 is a block diagram to explain the principle a first embodiment of the playback system according to the invention,

Fig. 2 is a block diagram of a second embodiment the playback system according to the invention,

]? ig. 3 is a circuit diagram of an embodiment of the electrical Circuit of an essential rope of the 'block diagram according to Pig. 2,

Pig. 4 is a graph of a phase correction curve of the phase correction circuit after Pig. 3,

Pig. 5 shows a block diagram of a third embodiment the playback system according to the invention,

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ORIGINAL

Pig. 6 is a circuit diagram of an embodiment of an electrical circuit that includes an essential Hail of the block diagram according to Pig. 5 forms,

Pig. 7 is a curve diagram of the phase difference characteristic between the two channel signals of the channel signal phase shift circuit,

Pig. 8 is a circuit diagram of a modified embodiment the electrical circuit, which is an essential part of the circuit according to Pig. 6 forms,

Pig. 9 is a graph of a frequency-phase characteristic the phase shift circuit according to Pig. 8th,

Pig. 10 is an electrical circuit diagram of a fourth embodiment form of the playback system according to the invention and

Pig. 11 is a graph showing a frequency-phase shift characteristic the phase shift circuit according to Pig. 10.

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FIG. 1 shows a block diagram of a theoretical first embodiment of the system according to the invention. A left channel signal L and a right channel signal R supplied to the input terminals 11 and 12, respectively. go through preamplifiers 13 and 14 and are in Output amplifiers 15 and 16 amplified. The signals L and R, which have thus been amplified, are placed in a loudspeaker 18 placed on the left front side of a listener 17 is, or a loudspeaker 19 »which is arranged on the right front side of the listener 17, fed to and from these Speakers radiated. Meanwhile, the signals L and R that passed through the preamplifiers 13 and 14 are

gen are fed to the base of transistors 21 and 22 of a matrix circuit 20, which is shown by a dashed line. A resistor 24 connected to the emitter of the transistor 21 and a resistor 25 connected to the collector of the transistor 22 are connected to an amplifier 27 together. A resistor 23, which is connected to the collector of the transistor 21, and a V / resistor 26, which is connected to the emitter of the transistor 22, are connected together to an amplifier 28. Signals + L and -L appear as output signals at the emitter and collector of transistor 21, whereas signals + R and -R appear as output signals at the emitter and collector of transistor 22, respectively. A differential signal (LR) is thus supplied to the amplifier 27 and a differential signal (RL) is supplied to the amplifier 28. The signals (LR) and (RL), which are amplified by the amplifiers 27 and 28, respectively, are corresponding to a speaker 29 'of _w on the left rear side of the RERS Hö 17 is disposed, and a loudspeaker 30 supplied at the right back of the listener is arranged, and they are reproduced and set to music through these speakers.

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The difference signals (L-R) and (R-L) will now be detailed considered. In these difference signals are the components (the direct sound components) that are in the signals L. and R have the same amplitude and phase, cancel each other out and they do not exist in these signals. Consequently is the direct sound, the sound source is not included in these difference signals) but only the indirect ones Sound components such as reflected sound components and room reverberation components.

Accordingly, only the indirect sound components, for example the reflected sound components and the Reverberation sound components radiated from the loudspeakers 29 or 30 to the listener 17 as effective sound components and it becomes a four-channel stereophonic reproduction artificially on the basis of a two-channel sound program source manufactured. In this way a stereophonic sound field is formed, which is more realistic has, as the sound field of a two-channel playback system, in which only those located on the front Speakers 18 and 19 can be used.

However, there still remains the problem that in the event that the two channel signals L and R have different components which are different from one another in their amplitude and in their phase, the direct sound components in ' the difference signals (L-R) and (ft-L) are included. One An embodiment in which this problem is solved is described with reference to FIGS.

Figure 2 is a block diagram of the second embodiment of the plant according to the invention. In Figures 1 and 2 are the same components are given the same reference numerals and their description is therefore omitted. A Left channel signal L and right channel signal R supplied to input terminals 11 and 12, respectively, go

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through the preamplifier 13 "or 14 and are the loudspeaker 18 arranged on the left front side or the loudspeaker 19 arranged on the right front side Via amplifier 15 or 16, as it is with reference to the first embodiment has been described, and they are reproduced and radiated through these speakers.

On the other hand, the left channel signal L and the right channel signal R are fed to an amplitude correction circuit 40 and their amplitude is corrected there. The amplitude correction circuit outputs signals L 'and R ¹ whose amplitude is corrected. An output signal L '· of the amplitude correction circuit 40 is fed to a phase correction circuit 41, in which the signal is corrected in its phase, as will be described later. The phase-corrected signal L ¹ θ is then fed to a matrix circuit 42. An output signal R ^{1 of} the amplitude correction circuit 40 is also supplied to the matrix circuit 42. The signals L ¹ Q and R ¹ are matrixed in the matrix circuit 42 and the output ^{signals (L 'θ -R 1} and Oil ¹ -L ¹ Q) of the matrix circuit 42 are amplified in the amplifiers 27 and 28, respectively. The signals amplified in this way are reproduced in the rear speakers 29 and 30 and emitted.

FIG. 3 is a circuit diagram of an embodiment of an electrical circuit of the essential part of the block diagram shown in FIG. The amplitude correction circuit 40 includes two channel equalization volume controls and 51 connected to each other. By setting sliders for volume controls 50 and 51 together are made, the direct sound components in the left channel and the right channel, namely L and R adjusted so that they are equal in amplitude.

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The amplitude-corrected signal L ^f, which has been taken from the slide of the loudness regulator 50, is fed to the phase correction circuit 41 via a coupling capacitor 53 of the base of a transistor 52. A phase changing circuit consisting of a variable resistor 54 and a capacitor is composed ^ is connected between the collector and the emitter of the transistor. Base bias resistors 56 and 57 are connected to the base of the transistor 52, and a collector resistor 58 and an emitter resistor 59 are connected to the collector and the emitter of the transistor 52, respectively. It is possible to change the phase θ of the signal L '> sc ^ as shown in FIG. When the resistance of resistor 54 is changed from Ra to Rd, where Ra>Rb>Rc> Rd, the phase characteristics corresponding to these values Ra to Rd change as shown by curves Pa, Pb, Pc and Pd is shown in FIG. Correspondingly, the output signal of the phase correction circuit 41, which is emitted from the junction between the variable resistor 54 and the capacitor ^ , is supplied via a coupling capacitor 61 to the base of a transistor 60 of the matrix ^{circuit 42 as a signal L 1} θ which is sent to the left channel Corresponds to signal L, which is corrected in its amplitude and phase.

The transistor 60 and a transistor 62 of the matrix circuit are each connected to their emitter and collector with emitter resistors 63 or 64 and collector resistors 65 or .66 connected. Base ^ before ^ resistors 67, 68, 69 and 70 are connected to the base of transistors 60 and 62, respectively. A capacitor 71 and a V / resistor 72 are connected to the collector of the transistor 60 connected in series, and a capacitor and a resistor 74 are connected in series with its emitter. The connection point 80, the resistors 74 and 76

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is connected to the amplifier 27. The connection point between resistors 72 and 78 is to the amplifier

28 connected. The output signal R ^{1 of} the slider of the volume control 51 becomes the base of the transistor 62 directly. fed through a coupling capacitor 79. ^{Signals L 1} 0 and -L ¹ θ can be picked up from the emitter and the collector of transistor 60. ^{Signals R 1} and -R ¹ can be picked up from the emitter and collector of transistor 62, respectively. Consequently, these signals are matrixed by the resistors 72, 74, 76 and 78, and a difference signal (L 'θ -R ¹ ) results at the connection point 80 / while a difference signal (R ^f -L' Θ) results at the connection point 81 results. These difference signals (L ¹ Q-R ') and' (R ¹ - L ¹ Θ) are from the rear speakers

29 and 30 emitted.

In the system according to the invention, the amplitudes and the phases of the left channel signals L and the right channel signals R adjusted so that the difference signals do not contain the direct sound component, but only the indirect sound components.

The amplitude correction circuit 40 and the phase correction circuit 41 can be used to have an effect volume in a so-called delay reverberation effect device represent in order to generate a certain necessary output signal.

A closer examination of the difference signals in the first Embodiment shows that the realism is not sufficient, since the low-frequency components in the Signals are missing. In this case, a reproduction sound field is formed by the indirect sound, which creates a loose, creates a scattered impression. A sound field reproduced in this way causes the listener to feel a slight inconsistency.

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or a feeling of disharmony or psychological instability. Reflected sound or reverberation sound, reaching the ear of a listener in a real concert hall contains sound with a low frequency component, which has very great energy. The indirect sound component in the two channel signals L and R also contains many low frequency sound components. In most cases, the low frequency sound component is common contained in the left channel signals and the right channel signals with the same phase and the same amplitude. if composes the difference signal from the same amplitudes is, most of the low-frequency sound component will no longer be present in the difference signal. An embodiment which avoids this problem is described below.

Figure 5 is a block diagram of a third embodiment the plant according to the invention. In Figures 1 and 5, the same components are provided with the same reference numerals and its description is therefore omitted. The left channel signals L and the right channel signals R become supplied via the terminals 11 and 12 at the input and they go through the preamplifiers 13 and 14, respectively. The signals are then sent to a setting circuit 90 on the one hand supplied with changeable crosstalk. The two signals L and R are, as described below, in the size of their crosstalk amount of the same phase is set in the crosstalk variable setting circuit 90 and converted into signals + Li and + Ri. The signals + Li and + Ri pass through amplifiers 15 and 16, respectively, in which they are converted into signals -Li and -Ri and reproduced and emitted by the loudspeaker 18 and 19, respectively.

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The left-channel signal L and the right-channel signal R of the preamplifiers 13 and 14, on the other hand, are phase shifting, circuits 91 and 92 respectively. Parts of the two signals L and R are correspondingly inverted (changed) in their phases in accordance with the low-frequency sound components that are only present in the phase shift circuits 91 and 92, as a result of which signals + LA θ and + Ra θ modified from the signals will. The signals -L and + LA © v / ground from the phase shift circuit 91 of the matrix circuit 93 is supplied. The -R and + RA θ signals are fed by the phase shift circuit 92 of FIG Matrix circuit 93 is supplied.

Difference signals - (L'-R ¹ AO) and - (R'-L'aQ), which are set in their amplitude and are matrixed in the matrix circuit 93, are fed to a channel signal phase shift circuit 94 and 95, respectively, in'der they get a phase difference Ψ within 90 degrees from each other. The output signals - Γ (L ¹ -R ¹ AQ) * ΑφΛ and - j (R'-LΆ θ) αφ Λ of the channel signal phase shifting circuits 94 and 95 go through gain and frequency characteristic ^ compensation circuits 96 and 97 ^ and they are of the rear speakers 29 and 30 reproduced and radiated.

Even if the input signals to the terminals 11 and 12 are supplied, monorale signals can be multidimensional stereophonic reproduction sound field artificially because of a low-frequency component of the signals that reproduced as rear signals.

In Figure 6 is a circuit diagram of an embodiment of a specific electrical circuit is shown, which is an essential Forms part of the block diagram according to FIG. The variable crosstalk adjustment circuit 90 adjusts the magnitude of the crosstalk between the left channel L and the right channel R via a variable resistor 100,

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so that the separation between the two channels varies, for example, within a range of 8 dB up to 20 dB can be. This changeable setting makes it possible to create an effect in which the alignment the sound source to be reproduced in the reproduced sound field in forward and backward directions is moved. The left channel signal L and the right channel signal R are in the setting circuit 90 for changeable Cross-talk of the phase and converted into signals Li and Ri, which have a modified information content to have. The signals Li and Ri are fed to an amplifier 15 and 16, respectively, which are essentially one Transistor 103 and 104 included in emitter-base circuit. The output signals -Li and -Ri of the amplifiers 15 and 16 are reproduced and radiated from the front speakers 18 and 19, respectively, as described above. In the description available so far and in the following description, the positive and negative meanings the polarities of these signals on the signals. If a circuit that is constructed differently than the Circuit according to Figure 6; is used, then result different polarities of the signals than in the circuit described so far.

In the meantime, the left channel signal L and the right channel signal R are switched through a capacitor 107 and a Capacitor 108 is supplied to the besis of a transistor 105 and a transistor 106, respectively. Leave the -L and -R signals decrease at the collector resistors 109 and 110 of the transistor 105 and the transistor 106 and the signals + L and + R can be taken from the emitter resistors 111 and 112 <of the same transistors. The signals -L and -R taken from the collectors of the transistors 105 and 106 become V / i resistors 119 and 122 of a matrix circuit 93 supplied via capacitors 113 and 114, respectively.

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The signals + L and + R _; which can be removed from the emitters of the transistors 105 and 106 are in their phase in the low-frequency component by a phase shift circuit consisting of a capacitor 115 and a resistor 116, which are connected between the emitter and the collector of the transistor 105 and one Phase shift circuit consisting of a capacitor 117 and a resistor 118 connected between the emitter and collector of the transistor 106, inverted. The signals are thus changed to modified signals + LA θ and + RAO. These signals + LA θ and + RA θ are supplied to a resistor 121 and a resistor 120 of the matrix circuit 93, respectively. A desirable low frequency at which the phase should be inverted can be selected by appropriately selecting the capacitance values of the capacitors 115 and 117 and the resistance values of the resistors 116 and 118.

In the phase shifter circuits 91 and 92 constructed in this way are, as shown in Figure 6, the amount of phase shift in the low-frequency part of the original Signals + L and + R closed when the frequency decreases. Accordingly, in the above-described Circuits do not uniformly phase a signal at all low frequencies to 180 degrees from the phase of the original Signal shifted (like a phase reversal in the true sense of the word). The opposite Signal which is inverted in phase in a desired low frequency range according to the invention. "' a modified signal obtained from the phase shift circuit 91 and the phase shift circuit 92, respectively and which in phase in a desired low frequency range with respect to the phase of the original signal is changed. Again, the polarities of the signals are

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obtained from the phase shift circuits 91 and 92, different, which depends on the structure of the circuits 91 and 92. The polarities only need to be designed in such a way that that the difference signals can be received in the matrix circuit 93 and that they are not based on those Differential signals are limited in the embodiment described above.

Input lines 125 and 126 of the setting circuit 90 with variable crosstalk can be designated with points 127 and 128 at the emitters of the transistors 105 and 106 of the phase shift circuit 91 and 92 be connected.

In the matrix circuit 93, a variable resistor 123 is connected between the resistors 119 and 120 ", On variable resistor 124 mechanically connected to variable resistor 123 is between the Resistors 121 and 122 switched. Because of the resistors 119 and 120 and the variable resistor 123 the signal -L, which is taken from the collector of the resistor 105, and the signal + RAO ^ which from the emitter of the Transistor 106 is tapped, mixed together, and a resulting difference signal is an output signal at the slide of the variable resistor 123, which is fed to a variable resistor 129. Because of the resistors 121 and 122 and the variable resistor 124, the signal.-R is from the collector of the transistor 106 and the signal + LA θ from the emitter of transistor 105 mixed together ^ and a resulting difference signal is an output signal at the slider of the variable resistor,,, Stand 124yand it is a variable resistor 130 which is mechanically coupled to the variable resistor 129.

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The signals -L and + RAO and the signals -R. and + LA θ are mutually mixed with one another to form difference signals {- (L-RAO) j- and i- (R-LAk 0) £. It should be noted here that the modified signals RA θ and LAQ derived from the signals L and R are obtained by inverting the phases of the signals L and R in the low frequency range ( Accordingly, the low-frequency parts in the difference signals -J- (L-RA 0) 1 and X- (R-LA Q) J- as sum signals U are the low-frequency component of the signal L) + (the low-frequency component of the signal R. ) around U the low-frequency component of the signal R) + (the low-frequency component of the signal L) j . The remaining parts of the modified signals RAO and LAO, which have been inverted (changed) in phase, become difference signals whose Composition is similar to that of a simple difference signal, and accordingly the difference signals £ - (L-RA O) (and / - (R-LA O) J- contain a sufficient proportion of low-frequency components so that an artificial stereophonic reproduction sound field d can be obtained with a vivid sense of reality when these signals are reproduced and radiated from the rear speakers.

By adjusting the mechanically coupled variable resistors 123 and 124, the amplitude ratio of the corresponding channel signals compared to the ratio 1: 1. Especially if the corresponding The slide of the variable resistors 123 and 124 is in its middle position, then a Mixing ratio of the -L signal and the + RA 0 signal and the -R signal and the + LA 0 signal of 1: 1 each. However, if the slides are in positions that are shifted in relation to the middle position, then the ... mixing ratio of the signal -L to the signal + RA is 0 and the mixing ratio of the -R signal to the signal

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shifted compared to the ratio 1: 1.

The output difference signals of the matrix circuit 93 in which the mixing ratio is shifted from the ratio 1: 1 can be expressed by the expressions - ^ j- (L'-R) J and j- (R'-L ¹ Δ θ) j- . If the mixing ratio can be changed in the above-mentioned manner, then part of the signal component that would have been lost by mixing the signals without changing the signal amplitude, ie a mixing ratio of 1: 1, is retained in a difference signal. As a result, the sound quality of the difference signal itself is improved, and the stability of the entire playback sound field is increased. In this way a reproduced sound field can be achieved which does not leave a listener in any unstable way or feelings of disharmony.

The output difference signals i- (L'-R ¹ A 9) j and | _- (R'-L ¹ AO) r of the matrix circuit 93 are adjusted in amplitude by the variable resistors 129 and 130 and they then become the base of the transistor 131 and the transistor 132 of the channel signal phase shift circuit 94 and 95, respectively. A resistor 133 and a capacitor 134 are connected between the collector and the emitter of the transistor 131. Resistor 135 and capacitor 136 are connected between the collector and emitter of transistor 132. Output signals can be taken from the connection point between resistor 133 and capacitor 134 and the connection point between resistor 135 and capacitor 136.

A form of frequency-phase shift characteristic between the two channel signals for the channel signal phase shifting circuits 94 and 95 are in curves I and II in Figure 7 shown. According to the characteristic curves in this embodiment is the phase shift between the two channel signals at both low and high sound frequencies

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small amount. However, modifications can be made, for example. be made that the phase difference between the two channel signals over the entire sound frequency range is made uniform or that the phase difference between the two channel signals is in a low frequency range is made small and uniformly large in other frequency ranges.

The difference signals j- (L'-R-Δ Θ) ΔΦ ^ and (- (R'-L ¹ AG) A (which have received a phase difference between the two channel signals within 90 degrees in the channel signal phase shift circuit 94 and 95, are fed to the amplifier and frequency compensation circuits 96 and 97, respectively, corresponding to the base of the transistor 137 "and 138. In this case, the phase difference between the angles φ ^ and Φ ρ should be kept within 90 degrees at the most. As already described above; the phases of the signal components of opposite phase, which are contained relatively superfluously in both difference signals, are shifted from an opposite phase relationship in the channel signal phase shifting circuits 94 and 95. Thus, the sound of the reproduced sound field is aligned by the rear signals to a certain extent and the sound of the indirect sound components generated from the backward signals is almost natural, whereby ma n maintains the feeling of certainty and space.

The amplifier and frequency compensation circuits 96 and contain amplifier circuits with transistors 137 "resp. and prior art CR tone quality adjustment circuits having resistors 139 "through 142, capacitors 147 and 148," a switch 151, resistors 143 to 146, capacitors 149 and 150, and a switch 152. The signals applied to the desired amplitude have been amplified and their frequency characteristics corresponding to the high frequency components, of distortion, noise components, etc. in the

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Circuits 96 and 97 have been compensated for as indirect sound from the rear speakers 29 and 30 reproduced and radiated. This gives you an exceptionally good, four-channel, stereophonic reproduction sound field.

An example of another modified circuit arrangement of the phase shift circuits 91 and 92, the matrix circuit 93 and the channel signal phase shifting circuits 94 and 95, which have been described with reference to FIG. 6, is shown in FIG Figure 8 shown. In Figures 6 and 8, the same components are given the same reference numerals, and they are not described again. According to Figure 8, the signal -L from the collector of the transistor 105 and the signal + RAG from the emitter of transistor 106 through resistors 160 and 162 mixed. The -R signal from the collector of transistor 106 and the + La θ signal from the emitter of transistor 105 are mixed by resistors 163 and 161 accordingly and matriculated.

In the variable crosstalk control circuit 90 for the left channel signals and the right channel signals, ei $ in-phase crosstalk, e.g. (0.92L + 0.38R) or (0.92R + 0.38L) is generated. In the phases - shift circuits 91 and 92 and in the matrix circuit 93 for the rear left channel signals and the rear right channel signals crosstalk is generated in opposite phase, for example (0.92L - 0.38R) or (0.92R - 0.38L). In the present embodiment, the crosstalk is in opposite phase at 32 Herz and at higher frequencies generated. In the difference signal of the two channel signals L and R leave the low frequency signals, which are almost monoral signals, in one Frequency range below 30 hearts a little bit different

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Waveforms when they are deleted against each other. This residual curve shape creates distortions and blurring in the Sound. In order to avoid the occurrence of such residual waveforms, in-phase cross-talk is used at frequencies provided below 30 hearts, which has no effect on the stereophonic effect.

The difference signals that have been cross-talked in opposite phase are fed to the control electrodes of field effect transistors (FET) 164 and 165. When the impedances of resistors 133 and 135 connected to the drain electrodes of field effect transistors 164 and 165 are less than the impedances of capacitors 134 and 136 connected to their source electrodes, the signals flow away from the drain electrodes. When the impedances of resistors 133 and 135 are made larger than the impedances of capacitors 134 and 136, the signals flow away from the source electrodes. On the other hand, the drain electrode is in antiphase and the drain electrode is in phase with the control electrode. Consequently, the phase characteristic at low frequencies is 0 degrees, and it reaches minus 180 degrees _; as the frequency increases, as shown in FIG. The frequency at which the impedance of the resistor and the impedance of the capacitor coincide with each other is the shift frequency, which becomes minus 90 degrees.

In the present embodiment, the resistance values of the resistors 133 and 135 are 8.2 K2 and 6.8 KΩ, respectively, whereas the capacitance values of the capacitors 134 and 136 are 0.22yUF and 0.04 / UF. The frequency f ^ at which the Phase is lagging by 90 degrees with respect to the channel arrangement of the field effect transistor 164

f = \ = 88 Hz

¹ 2wx 8.2 χ 10 ^J χ 0.22 χ 10 ~ °

The frequency fp, which the channel arrangement of the field effect tran. _χ sistors 165 concerns _; is

f ₂ = 1 = 500 Hz

2 «χ 6.8 χ ΙΟ ³ χ 0.047 x 10 ~ ⁶

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FIG. 10 shows a circuit diagram of a fourth embodiment of a device which can be used in the system according to the invention. The left channel signal L and the right channel signal R from the input terminals 11 and 12 are coupled via coupling circuits comprising a resistor 172 and a capacitor 173 and a resistor 174 and a capacitor 175, the bases of a transistor 176 and a transistor 177 and amplifier circuits 170 and 170, respectively 171 supplied. There are resistors 178, 179, 180 and 181 ansi factors as Basisvorspannungswiderstände for the 'T _r 176 and 177 are provided. Resistors 182 and 183 are collector resistors and emitter resistors of transistor 176, respectively. Resistors 184 and 185 are collector resistors and emitter resistors of transistor 177.

A resistor 186 is connected between the emitter of transistor 176 and the emitter of transistor 177. The resistance 186, which is connected between the two amplifier circuits 170 171, causes signals in the amplifier circuits, be overlooked in the opposite phase. Accordingly, differential signals are obtained which are in opposite directions Phase to each other, in the corresponding Amplifier Circuits 170 and 17I. In particular, reinforced the transistor 176 of the amplifier circuit 170 the input signal L, which is fed to its base, and the Signal R, which is fed to the emitter of transistor 177 and which via resistor 186, the emitter of the Transistor 176 is supplied, and produces a difference signal i_ (L-tt R) jan his collector. The transistor 177 the amplifier circuit 171 accordingly amplifies the input signal R which is supplied to its base ^ and that Signal Ljwhich is formed at the emitter of transistor 176 and which is fed to the emitter of transistor 177 through resistor 186, and gives a difference signal t J- (R-α L) / to its collector.

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The coefficient α in the above difference signals changes with the resistance of the ■ emitter resistors 183 and 185 of transistors 176 and 177, respectively, and resistor 186. The crosstalk value associated with the opposite Channel signal in .G opposite phase, and which is present between the two amplifier circuits 170 and 171, can be on a desired value can be set by taking the resistance values of the above-mentioned resistors can be selected appropriately. For example, if the coefficient α is selected to be 0.5, the result is very good.

The difference signal £ - (L-α R) j, which is formed at the collector of the transistor 176, passes through a capacitor 187, and it is after it is in a low frequency amplifier circuit, a capacitor 189 and a resistor connected in series 190 contains, has been amplified in a low-frequency signal component, taken from a slider 191a of a variable resistor 191. A difference signal (- (Ra L) T ^{- formed} at the collector of transistor 177 passes through capacitor 188 and, after passing through a low frequency amplifier circuit comprising capacitor 192 * "and one in series resistor 193 connected for this purpose, has been amplified in its low-frequency signal component has been taken from the output of a slide 194a of a variable resistor 194. The output signals of the slide 191a and 194a of the variable resistors 191 and 194 are connected via coupling circuits consisting of capacitors 199 and and resistors 201 and 202 are fed to the bases of transistors 197 and 198 of phase shift circuits 195 and 195 respectively,

When the above-described low-frequency amplifier circuit is constructed so that the signal amplitudes of the low-frequency

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Sounds are relatively amplified by the fact that the signal amplitudes in the medium and high sound frequency ranges are lowered, an amplifier circuit is generally required. In the present embodiment, however, the circuits of transistors 176 and Reinforcements, so that no special amplifier circuit is necessary. "Further, if the low-frequency amplifier circuit is made to have a characteristic such that it has differences in frequency domain characteristic between the two channels can compensate, which occurs when the phase shifting circuits 195 and 196, the are to be described later, have frequency characteristics that are different from each other, then a Device can be provided with a balanced characteristic curve between the two channels with relatively few components.

In phase shift circuits 195 and 196, resistors 203, 204 and resistors 205 and 206 are the bias resistors of transistors 197 and 198. Resistors 207 and 209 are provided as collector resistors and resistors 208 and 210 are provided as emitter resistors of transistors 197 and 193. A resistor 211 and a capacitor 212 are connected between the collector and the emitter of the transistor 197. Resistor 213 and capacitor 214 are connected between the collector and emitter of transistor 198. The output signal of the phase shift circuit 195 can be taken from a connection point of the resistor 211 and the capacitor 212 and the output signal of the phase shift circuit can be taken from a connection point of the resistor 213 and the capacitor 214.

The output signals of the phase shift circuits 195 and

are signals {(L-α R) A ^ and [(R- «L) 4 * ₂ |, which signals

in the vicinity of an acoustically desired frequency band

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and which have a phase difference of less than 90 degrees from one another. The frequency of phase-shift characteristics of the phase shift circuits 195 and 196 are shown in Figure 11. "The frequencies f ^ and f _2, which are shown in Figure 11 _r can be expressed by the following equations

^C 212 ^R 211

(1)

2 «C ₂₁₄ R

f
2 ~

where C ₂₁ 2 "^ C ₂ -J 4 are capacitance values of capacitors 212 and 214 and R ₂₁₁ and R ₂ -Jx are resistance values of resistors 211 and 213.

The output signals [(L-α R) ^Δ ^ J and £ (R-OL) A ⁹ J "which are given from the phase shifting circuits 195 and 196 to resistors 217 and 218 via capacitors 215 and 216 are output terminals 219 and 220 The phase difference in the vicinity of the acoustically required frequency range is ^ - ^ ₂ = 90 degrees. Because of the phase difference of about 90 degrees, which are provided for the two indirect rear signals of both frequencies below a few KHz with the aid of the phase shifting circuits 195 and 196, You can hear right-sided reverberation from the right side of the sound reproduction field and left-sided reverberation from the left side of this field. This prevents the unnatural feeling due to lack of orientation, which can occur when the two channel signals are composed of mutually opposite phases.

The following is an example of the size of each circuit element which is used in the circuit shown in FIG

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is provided, indicated:

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resistance

172, 174

178, 180

179, 181

182, 184

183, 185 186
190, 193

207, 210

208, 209 211

213

217, 218

173, 175 187, 188 189, 192 212

214

215, 216

The frequencies f ^ and fp based on the above Sizes are calculated »are

capacitor

470 K2 / UF / 25V
/ / UF / 25V Il / Uli?
/ 270 Ka / UF 5.6 KQ 0.047 '/ UF I! 0.68 5.6 KQ 8.2 KQ 4.7 KQ 4.7 KQ 8.2 KQ 6.8 KQ 68 K2 1 / UF / 50V 3.3 0.1. 0.22

2 * χ 0.022 χ 10 ~ ^b χ 8.2 χ 10 ³

= 88 Hz

f ο ⁼

2irx 0.047 x 10 ~ ^b χ 6.8 χ 1C?

= 500 Hz

As a result, the sound from the left rear speaker at 88 Hz has a phase difference of 90 degrees relative to the sound of the left front speaker. The sound of the right rear loudspeaker has at 500 Hz a phase difference of 90 degrees from the sound of the right front speaker. On the other hand, he has

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Sound from the left and right rear speakers in a wide frequency range with a center frequency of 300 Hz a phase difference of 90 degrees.

In the meantime, the input signals L and R from the input terminals 11 and 12 are inputted through resistors 221 and 222 and capacitors 223 and 224 to the bases of the transistors 225 and 226, respectively. The collector output of the transistor 225 is output from an output terminal 229 through a capacitor 227 and a resistor 228. The collector output signal of the transistor 226 is output from an output terminal 232 via a capacitor 230 and a resistor 231. The resistors 228 and 231 are connected to one another by a resistor 233. As a result, the output signals of transistors 225 and 226 are cross-talked over in phase, and signals (L + α R) and (R + et L) are generated at terminals 229 and 232.

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Claims (10)

6831 claims Multi-dimensional stereophonic .Playback system, characterized in that a first circuit is provided for the playback and emission of signals from several channels, which have a direct Scballkoioponente and an indirect Scballomponent , from loudspeakers (18, 1 <$ »which are each assigned to one of the channels that the loudspeakers are arranged in front of a listener, that a second circuit is provided which processes the signals of the various channels in a matrix (20), whereby difference signals of each channel signal are obtained, and that these difference signals are reproduced by loudspeakers (29 »30) or radiated, which are arranged next to or behind the listener, the direct scball component is canceled out in these difference signals and they essentially only have the indirect sound components. 2. playback system according to claim 1, characterized in that an amplitude correction circuit (40) for correcting the amplitude of the signals which is provided in different channels, and that a phase correction circuit (41) is provided for correcting the phase of the various signals, which are matrixed with dan signals which have been corrected in ibrer amplitude, and that the second circuit mairiLziert a signal which has been corrected in its phase by the phase correcting circuit _t and a signal not passed through the phase correction circuit which has not been corrected in its phase. ../30 209817/0776 2U6197 3. Playback system according to spoke 1, characterized that the second circuit comprises P base shift circuits (91 * 92} through which Phase of the biological component of the signals from several Channels are inverted and that a matrix circuit (93) is provided * which inverts the signals in the low-frequency Schairbereich by the phase inverter circuit and the signals of the channels which are different from the channels of the signals inverted in phase, whose signals have not been inverted in phase to thereby obtain differential signals, matrixed. 4 «playback system according to claim 3» thereby ge - indicates that the matrix circuit (93) via a circuit (123, 124} with variable resistance in which a mixing ratio can be changed, takes differential signals of the signals, which in their phase in the lower frequency range by the phase inverter circuit have been inverted, as well as signals from channels that are different from the channels for the inverted in phase Distinguish signals, whereby these signals are not inverted in their phase. 5- playback system according to claim 3, characterized that the second circuit further comprises a phase shift circuit (94, 95) for phase shifting each of the reference signals generated by the matrix circuit are matrixed in order to obtain a phase difference within 90 ° between the difference signals. 6. playback system according to claim 3, characterized in that the matrix circuit (93) the difference campaigns by crosstalking in opposite Phase receives, via a resistor (233) which has a certain resistance value, also the signals, ../31 209817/0776 2U6197 which have been inverted in their phase in their low frequency range by the inverter circuit, and further receiving the signals of the channels which are different from the channels for the phase inverted signals differ, in which case these signals are not inverted in their phase. 7. playback system according to claim 6, characterized in that the first circuit further comprises a device (100) in order to allow the various channels to cross talk to one another in phase, so as to produce sum signals to form, which have a certain crosstalk value. 8. playback system according to claim 1, characterized in that that the signals of the different channels are two channel signals L and R and that through the second Circuit differential signals (I-R) and (R-I) and the rear or speakers on the side. 9. playback system according to claim 1, characterized in that the signals of several channels are two Channel signals are L and R and that the second circuit has the two channel signals in opposite phase with each other lets talk over with a suitable endearing value to get difference signals (I-α R) and (R- (Λ) and these Differential signals through the rear or side speakers to reproduce or radiate from them. 10. Playback system according to claim 9, characterized in that the first circuit allows the two channel signals to crosstalk with each other in phase with the crosstalk value α, also generates signals (I + ⁰ R) and (R + «I) and generates these signals from the front Speakers can reproduce and radiate. 209817/0776